Matthew Poole and continuators on Genesis 38:26

26 And Judah acknowledged them , and said, She hath been more righteous than I : because that I gave her not to Shelah my son: and he knew her again no more .

His guilty conscience and the horrour of so foul a fact together with his sudden surprizal forced him to an ingenuous confession, whereas he might have used many pretences and evasions, which would easily have prevailed with such partial Judges.

She was more unchast, because she knowingly committed Adultery and Incest, when he designed neither; but he was more unjust, because he was the cause of her sin, both by withholding Shelah from her, who was hers both by right and by Iudahs promise, and by whom her chastity should have been preserved; and by his solicitation and encouragement of her to the sin.

Shewing the sincerity of his confession by his forsaking of the sin confessed. See Iob 34. 32. And it may be probably concluded that he neither knew her nor any other Woman afterward, because there is no mention of any Child which he had after this time.